Sub OpenfileSomma()
Dim strFile As String
Set sh = ThisWorkbook.sheets(1)
mFolder = "F:Downloadprova" ' <<<<<<<< da modificare
strFile = Dir(mFolder & "*.xls*")
Do While strFile <> ""
    Workbooks.Open mFolder & strFile
    sh.Range("A1").Value = sh.Range("A1").Value + Range("B14").Value
    ActiveWorkbook.Close False
    strFile = Dir
Loop
End Sub

Public Sub copia()
    Dim i As Integer
    Dim fg As String
    Dim objFSO As Object
    Dim objFolder As Object
    Dim objFile As Object
    Dim wk As Workbook
    Dim r As Long

    With Application
        .ScreenUpdating = False
    End With
    sPath = ThisWorkbook.Path    '& "
uova cartella"    '<< da Modificare
    Set objFSO = CreateObject("Scripting.FileSystemObject")
    Set objFolder = objFSO.GetFolder(sPath)
    totale = 0
    For Each objFile In objFolder.Files
        myname = Dir(objFile, vbNormal)
        If myname <> ThisWorkbook.Name Then
            Set wk = Workbooks.Open(objFile.Path)
            For i = 1 To wk.Sheets.Count
                fg = wk.Sheets(i).Name
                peso = wk.Sheets(fg).Range("b14")
                nome = wk.Name
                totale = totale + peso
            Next i
            wk.Close Savechanges:=False
            irow = ThisWorkbook.Sheets("foglio1").Range("a" & Rows.Count).End(xlUp).Row + 1

            ThisWorkbook.Sheets("foglio1").Cells(1, 1) = totale + ThisWorkbook.Sheets("foglio1").Cells(1, 1)
            Set wk = Nothing

        End If
    Next

    With Application
        .ScreenUpdating = True
    End With
    Set wk = Nothing
    Set sh = Nothing
    Set objFile = Nothing
    Set objFolder = Nothing
    Set objFSO = Nothing

End Sub